Thermoelectric heat pump assembly



Jan. 2,1968 T. M. ELFVING 3,360,942

THEHMOELECTRIC HEAT PUMP ASSEMBLY Filed April 18, 1966 3 heets-Sheet 1 v INVENTOR. THORE M. ELFVING fF/a. 2

v ATTORNEYS Jan. 2, 1968 T. M. ELFVING 3,360,942

THERMOELECTRIG HEAT PUMP ASSEMBLY Filed April 18, 1966 3 Sheets-Sheet 2 INVENTOR.

THORE M. ELFVING ATTORNEYS Jan. 2, 1968 I T.-M. ELI -VING 7 3,360,942

THERMOEILECTRIC HEAT PUMP ASSEMBLY Filed April 18, 1966 3 heets-Sheet 5 lOl F/ 6 INVENTOR THORE M ELFVlNG ATTORNEYS United States Patent 3,360,942 THERMOELECTRIC HEAT PUMP ASSEMBLY Thor-e M. Elfving, 433 Fairfax Ave.,

San Mateo, Calif. 94402 Filed Apr. 18, 1966, Ser. No. 543,322 26 Claims. (Cl. 62-3) The present invention is directed generally to thermoelectric apparatus and more particularly to thermoelectric heat pumping and generating devices of both the liquid to air; liquid to liquid; and air to air types for varying the temperature of a fluid media.

The invention is specifically directed to the design of improved couple or subcouple assemblies suitable for standardized mass manufacture and subsequent mounting into larger heat pump assemblies of any size or capacity by simply varying the number of such prefabricated couple or subcouple assemblies joined into the same.

The standardized couple or subcouple assemblies according to the invention include not only the semiconductor bodies with their junction bridges for heat transfer to liquid or air phases but also improved prestressing means for protection of the fragile semiconductor bodies and their critical joints against mechanical stresses of various types.

In my copending applications Ser. No. 460,209, filed June 1, 1965, entitled Thermoelectric Assemblies and Ser. No. 463,713, filed June 14, 1965, now Patent No. 3,273,347 entitled Thermoelectric Heat Pump Assembly, there have been described thermoelectric heat pumping and generating devices as well as subcouple and couple assemblies to be incorporated in such heat pump and generating devices of the liquid to liquid, liquid to air, and air to air types incorporating a novel approach or principle for protecting, by prestressing the semiconductor material and its critical joints to adjoining metal parts, from damage through shocks, vibration, thermal expansion and contraction, etc.

According to the above patent applications, a central prestressing force is directed to each individual subcouple or couple assembly, for obtaining and maintaining for each individual semiconductor layer and its critical joints, a uniform predetermined prestressing force. An air to air heat pump is described with the thermocouples employing finned tubing sections, as junction bridges, in combination with annularly arranged semiconductor bodies arranged in a linear array. A central bolt, threaded at both ends, and running inside said tubing sections, applies a uniform prestressing force along the centerline or axis which is independent of the number of the subcouples or couples in the array.

In the present invention there is provided air to liquid (air to ice) assemblies using finned tubing sections on the air side in combination with central means for applying a prestressing force. The means comprises a central bolt firmly affixed to the junction bridge on the liquid (ice) side and threaded at its free end. The finned tubing sections are secured by the bolt through suitable insulating means. According to the present invention, the junction bridges on the liquid phase side can be water pipe sections or other bodies of various types and shapes for receiving liquids to be cooled or frozen.

As mentioned in my copending application Ser. No. 463,713, the compressive force, obtained by the prestressing method according to the invention, can be so strong that a good electric and heat conductive connection is obtained between abutting portions of the assembly without soldering.

It is an object of this invention to provide a prestressed assembly of subcouple units including soldered critical joints, that is, semiconductor layers soldered to suitable "ice end members in contact with heat dissipating and/or absorbing members.

Another object of this invention is to provide subcouple or couple units comprising improved mounting means for assembling into large heat pumping or generating units devices of both liquid to air and air to air types.

Still another object of this invention is to provide ice freezing units of both water-cooled and liquid-cooled types comprising an individual thermocouple with a cold junction in the form of a plate, tube or container for the freezing of one or more pieces of ice. Such an ice-freezing unit, according to the invention, includes prestressing means and mounting means for assembling the unit itself as well as joining several units into larger ice freezing devices.

Further objects and advantages of this invention will appear from the following description and the accompanying drawings as well as from the claims annexed to and forming part of the specification.

Referring to the drawings:

FIGURE 1 shows an elevation view, partly in section, of two thermoelectric subcouples for air to air systems, according to the invention;

FIGURE 2 shows an elevation view, partly in section, of subcouples and couples for a liquid to air system;

FIGURE 3 is a view, partly in section, of a liquid to air system comprising couples, according to FIGURE 2, rotated to offset positions in an air conditioner conduit;

FIGURE 4 shows an elevation view, partly in section, of an air-cooled ice freezing unit;

FIGURE 5 shows an elevational view, partly in section, of another air-cooled ice freezing unit; and

FIGURE 6 shows an elevation view, partly in section, of a water-cooled ice freezing unit according to th invention.

Referring to FIGURE 1, there are shown two subcouples 10a and 10b of an air to air heat pump or generating device. The subcouples are of identical design except with regard to the conductivity type of the semiconductive bodies incorporated therein.

The n-type and p-type bodies 11, 12 are soldered in an annular arrangement between two annular copper washers 13, 14 and 16, 17, respectively. Each such group forms an n-type or p-type subcouple 18, 19, respectively, which can be provided with heat dissipating or heat absorbing members on both the hot and cold junction sides, respectively. According to the invention, finned tubing sections 21, 22 and 23, 24 are soldered or otherwise in contact with the washers 13, 14 and 16, 17 on the hot and cold junction side, respectively, of the subcouples. In this way, each is provided with two finned tubing sections of large heat transfer capacity. The subcouples are joined into a couple by a conductor 27 and joined to other couples by similar conductors 28 and 29. Each subcouple is individually prestressed by means of a central threaded bolt 31. The bolt is preferably stainless steel having low heat conductivity. The bolt 31 runs through the subcouple washers and the finned tubing sections on each side thereof and ties the whole assembly, including respective conductors 27, 28 and 29 together. This is achieved by nuts 32 engaging insulating washers 33.

The central bolts 31 extend through holes in side shields 34 and receive wing nuts 36. The hot and cold junction sides of the completed assembly are separated and insulated from each other by an insulating partition 37.

The described subcouple assemblies are identical in design and can be assembled into heat pumping systems of any size and capacity. The prestressing method, according to the invention, makes it possible to use finned tubing sections clamped to the copper Washers without need for soldering. Silver, nickel or chromium plating of abutting surfaces serves to prevent oxidization of the clamped joint. By eliminating soldering except for the critical joints, a thermoelectric heat pump can be assembled from small components into large systems which can be easily taken apart again for repair or exchange of parts.

The semiconductive bodies shown in FIGURE 1 were described as annularly arranged and soldered between copper washers. When the annular layer of semiconductive material comprises several bodies, each individual body can be soldered to its own copper members to form part-subcouples, which then are annularly arranged at the ends of the finned tubing sections so that the center is left free, instead of using washer-mounted subcouples.

Referring to FIGURE 2, there is shown couple units of a liquid to air heat pump provided with prestressing means in the form of a central bolt. The couple unit includes two subcouple groups, each comprising semiconductive layers 41 and 42 of n-type and p-type, respectively, mounted between copper members 43, 44 and 46, 47, respectively. Similar junction ends face each other with the liquid phase of the system in between. On the opposite junction ends of the described subcouple groups, there are mounted means for heat transfer to air comprising finned tubing sections 48, 49.

On the liquid side, the subcouple groups are in contact with the flattened sides of a metal pipe section 51 which forms a junction bridge therebetween. The finned tubing sections 48, 49, together with the subcouple groups on both sides of the water pipe section 51, form a thermoelectric couple through which a current can be passed from the top of one finned tubing section 48, through copper members 43, through semiconductive layers 41, through another copper member 44, through the water pipe section 51, through an adjacent copper member 47, another semiconductive layer of opposite type 42, another copper member 46, and through the finned tubing section 49.

The described couple is, according to the invention, compressed along its centerline by a stainless steel bolt 52, threaded at both ends, and extending centrally through the linear assembly from one end to the other. The bolt 52 is at both ends mounted to side plates 53. All parts are tied together in a strong mechanical bond by means of wing nuts 54.

The central bolt 52 is firmly affixed to one of the junction bridges, namely the pipe section forming the liquid side bridge. The central bolt 52 passes through the water pipe sections fiat walls to which it is secured by brazing or soldering. The central bolt 52 is insulated from the other junction bridges by a washer 56.

Because of the strong central compressive forces which can be applied to the described way, the only abutting surfaces which have to be soldered in the conductivity path are the critical joints between the semiconductive bodies and their copper members. As illustrated, several couple units can be joined into larger assemblies by suitable conductors 57 and nonconductive rings 58 joining the liquid phase pipe sections.

Abutting surfaces of components clamped together by the prestressing or compressing bolts can be provided with indentations and matching protrusions in order to increase surface contact areas for minimum electric and thermal resistance. Carefully machined and cleaned surfaces are, however, in most cases sufficient for obtaining pressure joints having negligible resistances.

With the wing nut arrangement shown in FIGURE 2, the contact resistances between the washers 44 and 47, respectively, and the water pipe section 51 can each be reduced to micro ohms, or below. By suitable plating the abutting surfaces, the low contact resistance can be maintained for prolonged periods of time. The joint can be protected from oxidization also by sealing with sealing compounds. A resistance of 10 micro ohms corresponds to a Joules heat of only .1 watt at a current of 100 amps passing the joint, which is negligible in a heat pumping system of this type.

The central bolt 52 can be provided with a spring element for control of the compressive force at each subcouple. The bolt passes through the water pipe section in front of the thermoelectric couple and causes turbulence of the fluid flowing in the pipe. This increases the heat transfer coefficient between the inside of the pipe and the fluid. The bolt, which is firmly affixed by brazing or soldering to the junction bridge, passes through the temperature zone of the opposite junction. An insulating sleeve 59 may be provided to thermally isolate the bolt from the opposite junction. Instead of passing the bolt through the water pipe section for an opposite two-sided mounting of the subcouples, two bolts can be affixed on the same side of a longer pipe section for a one-sided mounting. Many other alternatives for coupled structures according to the invention are obvious.

A liquid to air heat pump system, according to FIG- URE 2, can be used both as an air-cooled liquid cooler and as a water-cooled air conditioner. The liquid system can be made as a closed circulating system between an air-cooled liquid cooler and a remote heat exchanger for air cooling, similar to so-called split package air conditioning systems. A closed liquid circulating system can also serve as a thermal link in a thermoelectric cascade in which the first stage comprises an air-cooled liquid cooler and the second stage is a liquid-cooled thermoelectric heat pump of either the liquid to air type or the liquid to liquid type. In the former case, the two heat pumps can both be of the type described.

The liquid to air couple units shown in FIGURE 2 are mounted between substantially parallel side pla es with subcouples and their prestressing bolts on each side of the liquid conduit and lying in one plane. In FIGURE 3, adjacent couple units are mounted with the prestressing bolts arranged perpendicular to one another. This is achieved by rotating adjacent couple units through by rotating the water pipe sections prior to sealing. A spiral arrangement of couple units can be achieved by rotating adjacent couple units through predetermined angles. In the figure, couple assemblies 61 and 62 are rotated 90". The subcouple assemblies 63, 64, 66, 67 are each affixed to respective pipe sections 68 by prestressing bolts 71, 72, 73, 74, respectively. The complete couple assemblies or units can be enclosed in a cylindrical insulated sheet metal conduit 76. The conduit, with liquid to air thermocouple units connected in series in the manner previously described, serves to direct air past the cooling fins while water or other liquid passes down the central conduit formed by the pipe sections 68. The complete unit can serve as a water-cooled air conditioner or an aircooled liquid cooler. Preferably, the central conduit is insulated by insulating members 77.

In FIGURE 4, there is shown an air-cooled ice freezer unit according to the invention. An inverted ice tray 81 is divided into small compartments by partition walls 82 to define pockets for the freezing of ice cubes. Water is sprayed into the pockets from underneath. A stainless steel bolt 83 is brazed in the center of the metal ice tray. The bolt 83 forms a central clamping means for n-type and p-type subcouples 86 and 87, respectively. The subcouples comprise semiconductive blocks or layers 88 and 89 of opposite type soldered between preferably silver or soft nickel plated copper discs 91, 92 and 93, 94. The subcouples are in thermal and electrical contact with the ice tray 81 through bodies of conductive material 96 and 97. On their hot junction side the subcouples are in contact with finned tubing sections 98 and 99. The whole assembly constitutes a thermoelectric couple unit which is energized through leads 101 and 102. When the assembly is energized, the ice tray with its adjoining conductor form the cold junction bridge for the couple.

The couple units are held together by a nut 103 on the bolt 83 acting through a strong insulated bar 106. Tightening of the nut exerts a strong central compressive force to the assembly. The central compressive force is so strong that no other soldering than that at the critical joints of the semiconductive layers is necessary. As shown in the drawing, the not junction side of the assembly is insulated from the ice tray by an insulation 108.

The ice freezing couple unit shown in FIGURE 4 is intended for use in the position shown, with water sprayed into the ice tray from underneath. The ice formed in the tray may be released by reversing the polarity of the direct current through the couple, whereby the ice tray becomes the hot junction.

The two subcouple assemblies attached to the ice tray can be mounted in several ways, for instance on opposite side walls instead of at the bottom of the tray. Instead of an ice tray, a water pipe section, other metal containers, tubes or plates can be used for a junction bridge. A cold junction in the form of a plate may receive other containers or trays which serve as compartments for the ice. The main feature of the unit shown is a couple unit comprising a metal junction bridge, a central metal bolt firmly attached to said junction bridge and subcouple units compressed against flat portions of said junction bridge by nuts or other suitable means attached to said bolts.

In FIGURE is shown another configuration of an air-cooled ice freezing couple unit according to the invention. An ice freezing metal body 111, in the form of an ice tray as previously described, or of any shape suitable for freezing ice therein or thereupon is provided with two flat areas 112, and 113, in the figures shown as side walls, in the middle of which stainless steel rods 114 and 115 are brazed. The fiat areas 112 and 113 can be provided with silveror electroless nickel-plated copper washers 116 and 117, preferably soldered thereto, and serving as extended bases for subcouple assemblies 128 and 129 comprising opposite types of annular semiconductive layers soldered between copper elements as previously described. The metal body 111 represents the cold junction bridge between said subcouples while the hot junction bridge elements in the form of finned tubing sections 120 and 121, respectively, are in contact with the subcouples on the hot junction side. The hot junction elements 120 and 121 are in electric contact with similar couple assemblies through conductors 122 and 123 as illustrated in the figures. The described couple assembly has each subcouple assembly prestressed by means of wing nuts 124 and 125 which engage insulating washers 126 and 127 to exert a strong clamping force to the associated subcouple assembly. The compressing forces obtained by the described prestressing means are so strong that sufficiently good press contacts can be obtained between the subcouple assemblies 128 and 129 and the washers 116 and 117 on one side and the finned tubing sections 120 and 121 on the other side thereof without requiring soldered joints. The abutting surfaces of such pressed contact joints in the electric path can be silverplated and otherwise treated for maintaining a low contact resistance over a long period of time.

In the described couple unit according to the invention, two bolts are firmly afiixed, each serving as central prestressing means for the subcouple assembly in an annular position around the same. Thus, as is shown by FIGURES 4 and 5, prestressing rods firmly afiixed to a junction bridge, according to the invention, can be centrally positioned in relation to semiconductor layers of both opposite types (FIGURE 4) and of the same type (FIGURE 5).

In FIGURE 6 is shown a water-cooled ice freezing couple unit with an ice tray 13-1 or a metal member 132 in thermal contact with the ice tray forming the cold junction bridge of the couple. Subcouple units of n-type and p-type material 133 and 134, comprising semiconductor layers soldered between copper washers, are bolted against ears 135 forming portions of said metal member 132. Threaded stainless steel bolts 136 and 137 are brazed to water pipe sections 138 and 139 in the manner previously described. The water pipe sections 138 and 139, respectively, form hot junction bridges. The bolts are insulated from the cold junction by means of insulating washers 141 and 142. The subcouple groups at each end of the cold junction are compressed by wing nuts 143 and 144, respectively.

The complete subcouples at each end of the metal member 132 can have all components soldered to each other and then prestressed by the bolt aflixed to the water pipe sections. It is, according to the invention, also possible to use press contacts between said components, as previously described, in which case the abutting surfaces at each joint can be silvered or otherwise treated to prevent oxidization.

The described ice freezing couple unit can be joined to other similar units to form large ice freezing assemblies by joining the water pipe sections between adjacent units in such a way that electric current passes serially from one thermocouple to the next. The ice tray, as well as the metal member attached to the ice tray, can be given a multitude of different shapes and positions toform couple units of various forms for various purposes.

As an example, it is possible to solder a water pipe section to the metal junction bridge 132, instead of an ice tray. The assembly shown in FIGURE 6 will then represent a liquid to liquid system with prestressed subcouples, according to the invention. Pipe sections attached to the junction bridge can, in the usual way, be joined into compound conduits by non-conductive members; for instance, by etched Teflon rings glued to the ends of the pipe sections by epoxy. Thus, in a liquid to liquid system, according to the invention, one pipe section systern will be provided with firmly atfixed bolts on one or both sides of each section, while the other sections are in metal, preferably soldered or brazed, contact with metal members serving as junction bridges between subcouples bolted to said first sections. As shown in my U.S. Patent No. 3,196,620, a great many variations of such assemblies are possible.

In the same way, many dilferent designs of liquid to air heat pumps can use prestressing rods firmly afiixed to junction bridge elements on the liquid side for securing one or two subcouples to said junction bridge elements to form a subcouple or couple group which can be joined into large assemblies as described in connection with the figures.

The principle of prestressing individual thermoelectric subcouple or couple assemblies by a bolt firmly affixed to one type of junction bridge element while insulated from the other junction bridge element can also be used in air to air subcouple or couple assemblies. In this case, the prestressing bolt can be firmly atfixed to a fin base of any type with a semiconductive annular layer in contact with said fin base in an annular arrangement with the bolt in the center thereof. A finned tubing section forms the other junction bridge and the bolt is extended through said finned tubing section and serves to clamp the junction bridge elements together as previously described. Such an air to air assembly is obtained by substituting conductive fins between the fiat areas 112 and 113 of the ice tray shown 'in FIGURE 5. The fins form cold junctions over which air can be passed in the usual way. The use of firmly afiixed bolts and rod on a junction bridge can, therefore, be applied to all types of thermoelectric heat pumps for prestressing or clamping purposes in connection with individual couples or subcouples.

The described method of using press contacts without soldering between abutting surfaces of components clamped together by compression bolts in thermoelectric assemblies, according to the invention, can only be used for suitable metals. While it is desirable from many viewpoints to use finned tubing sections or water pipe sections, like those shown in FIGURES 1 and 2, made entirely from aluminum, it is not possible to use press contacts against aluminum surfaces. Due to the almost instant oxidization of aluminum surfaces, the contact resistance at such surfaces amounts to 10 to 50 times the resistance obtained at copper surfaces of the same size at the same contact pressure. In view of the high currents used in thermoelectric assemblies, the voltage drop and the loules heat at pressure contact joints where aluminum surfaces are involved have proven prohibitive. Soft soldering to aluminum is a difficult process and it is, therefore, necessary for both press contacts and soldered contacts that aluminum components are provided with suitable abutting surfaces. According to the invention, this can be done in two different ways.

Referring to FIGURE 1, the finned tubing sections 21, 22, 23 and 24 can be made entirely from aluminum, preferably with so-called extruded fins. The copper washers 13, 14, 16 and 17 can, according to the invention, be secured to the ends of the respective tubings by soldering after first electroless nickel plating the ends of said tubings. The aluminum tubings provided with such copper washers or other suitable copper end elements secured thereto can now be soft-soldered to semiconductive layers or to other copper elements for good electric and heat contacts. Likewise, such tubings can, with their copper end elements, be pressed against other copper surfaces for good press contacts without soldering.

Referring to FIGURE 2, the shown finned tubing sections 48 and 49 can be made from aluminum and, after electroless nickel plating of the ends, soldered to the shown copper washers 43 and 46, respectively, or to other suitable end elements made from copper, and thereafter joined to semiconductive layers or to other copper washers by soft soldering. In the latter case, also, press contacts without soldering can be used. The shown water pipe sections 51 can also be made from electroless nickelplated aluminum and the copper washers 44 and 47 soldered thereto. It is also, according to the invention, possible to copperize or soft nickel-plate aluminum surfaces like the flat portion of the pipe sections 51 by electrolytic or spraying methods so that a thin layer of copper or nickel, in good contact with the supporting aluminum surface, is obtained. Aluminum surfaces treated in this way can be used for soft soldering or press contacts as previously described. In the same way, the junction bridges in the form of ice trays, etc., shown in FIGURES 4, and 6, can be made from aluminum and provided with copper discs soldered to their fiat surfaces for receiving subcouples or other components by soft soldering or press contact.

The invention is not limited to the designs shown in the figures but includes the general use of bolts firmly affixed to a junction bridge and serving, in combination with compression means, to prestress the critical joints at the semiconductive layers or blocks and to clamp various components together by central compression forces in thermoelectric couple assemblies of all types.

I claim:

1. An individual thermoelectric subcouple comprising a single semiconductive layer of n-type or p-type material, heat dissipating and heat absorbing junction bridge elements in electric and heat conductive connection With the hot and cold junction sides of said semiconductive layer,

metal conductors electrically connected to opposite sides of said semiconductive layer adapted to electrically connect to laterally adjacent individual subcouples to form thermoelectric couples having laterally adjacent subcouples, and compressing means for independently compressing each of said individual subcouples together to provide electrical and heat conductive pressure contact between the parts constituting said subcouples.

2. A thermoelectric subcouple as in claim 1 where said compressing means includes a rod affixed to one of said junction bridge elements.

3. A thermoelectric subcouple as in claim 1 where at least one of said junction bridge elements comprises a finned tubing section.

4. A thermoelectric subcouple as in claim 1 where both of said junction bridge elements comprise finned tubing sections.

5. A thermoelectric subcouple as in claim 2 where the junction bridge element to which the rod is affixed includes a finned metal member.

6. A thermoelectric couple assembly comprising a pair of subcouples one including a semiconductor layer of ntype material and the other of p-type material between metal elements, heat dissipating and heat absorbing bridge elements in electrical and heat conductive contact with said metal elements on the hot and cold junction sides of the layer, one of said bridge elements connected between similar junction ends of said subcouple, junction bridge elements connected to the other junction end of each of said subcouples, and means secured directly to said one of said junction bridge elements for applying compressive forces to said couple assembly.

7. A thermoelectric couple assembly as in claim 6 in which said one junction bridge element between similar junction ends comprises means for receiving a liquid.

8. A thermoelectric couple assembly as in claim 6 in which the junction bridge elements connected to the other junction end of said subcouples comprise finned tubing sections.

9. A theromoelectric couple assembly as in claim 6 in which said one junction bridge element between similar junction ends includes a fiat metal surface and in which the other junction bridge elements comprise water pipe sections.

10. in a thermoelectric heat pump assembly of the type including layers of semiconductor material of n-type and p-type each having first and second connective surfaces adapted to be electrically connected to first and second junction bridge elements respectively, a first junction bridge element adapted to be electrically connected to the corresponding surface of at least one of said semiconductor elements, a rod firmly secured to said first junction bridge element, a second bridge element adapted to be electrically connected to the other surface of said one semiconductor element, and compression means secured to said rod for forcing said first and second junction bridge elements toward said semiconductor layer.

11. A thermoelectric heat pump assembly as in claim 10 wherein said first junction bridge element is formed by a pipe section for passing a liquid therethrough.

12. A thermoelectric heat pump assembly as in claim 10 wherein said first junction bridge element includes a finned metal member.

13. In a thermoelectric heat pump assembly comprising semiconductor layers of n-type and p-type material having hot and cold junction surfaces, a first junction bridge element in electrical contact with similar junction ends of said semiconductor layers, a rod firmly secured to said junction bridge, second junction bridge elements in electrical contact with the other junction surface of said semiconductor layers, and means attached to said rod for forcing the junction bridge elements towards the respective surfaces of said semiconductor layers.

14. A thermoelectric heat pump assembly as in claim 13 wherein said first junction bridge element is formed by a pipe section for passing a liquid therethrough.

15. A thermoelectric heat pump assembly as in claim 13 wherein said first junction bridge element includes a finned metal member.

16. A thermoelectric subcouple assembly comprising a semiconductive layer of n-type or p-type material, heat dissipating and heat absorbing junction bridge elements in electric and heat conductive connection with said semiconductive layer on the respective hot and cold junction sides of said semiconductive layer, one of said junction bridge elements being in the form of a water pipe section, and compressing means including a rod firmly affixed to said Water pipe section disposed centrally in relation to said semiconductive layer for compressing the assembly together by forcing said heat dissipating and heat absorbing junction bridge elements towards said semiconductive layer.

17. A thermoelectric subcouple assembly comprising a semiconductive layer of n-type or p-type material, heat dissipating and heat absorbing junction bridge elements in electric and heat conductive connection with said semiconductive layer on the respective hot and cold junction sides of said semiconductive layer, one of said junction bridge elements being in the form of a metal member in which ice is frozen, and compressing means including a rod firmly affixed to said metal member disposed centrally in relation to said semiconductive layer for individually compressing the assembly together by forcing said heat dissipating and heat absorbing junction bridge elements towards said semiconductive layer.

18. A thermoelectric subcouple assembly comprising a semiconductive layer of n-type or p-type material, heat dissipating and heat absorbing junction bridge elements in electric and heat conductive contact with respective hot and cold junction sides of the semiconductive layer, one of said junction bridge elements including a fiat portion, and compressing means including a rod firmly afiixed to the flat portion of said junction bridge element disposed centrally in relation to said semiconductive layer for individually compressing the assembly together by forcing said heat dissipating and heat absorbing junction bridge elements towards said semiconductive layer.

19. A thermoelectric subcouple assembly comprising a semiconductive layer of n-type or p-type material with hot and cold junction sides, heat dissipating and 'heat absorbing junction bridge elements in electric and heat conductive contact with respective sides of said semiconductive layer, one of said junction bridge elements comprising a finned tubing section and the other comprising a metal body on which ice is frozen, and compressing means disposed centrally in relation to said semiconductive layer for individually compressing said assembly together to force said heat dissipating and heat absorbing junction bridge elements towards said semiconductive layer.

20. A thermoelectric couple assembly comprising a pair of subcouples one including a semiconductor layer of n-type material and the other of p-type material, heat dissipating and heat absorbing bridge elements in electrical and heat conductive contact with said semiconductor layers on the hot and cold junction sides of the same, one of said bridge elements including a flat metal surface and being connected between similar junction ends of said subcouple, junction bridge elements connected to the other junction end of each of said subcouples comprising finned tubing sections, and means secured to at least one of said junction bridge elements for applying compressive forces to said couple assembly.

21. In a thermoelectric heat pump assembly of the type including layers of semiconductor material of n-type and p-type each having first and second conductive surfaces adapted to be electrically connected to first and second junction bridge elements respectively, a first junction bridge element formed by a metal member for freezing ice thereon adapted to be electrically connected to the corresponding surface of at least one of said semiconductor elements, a rod firmly secured to said first junction bridge element,

a second bridge element adapted to be electrically connected to the other surface of said one semiconductor element, and compression means secured to said rod for forcing said first and second junction bridge elements towards said semiconductor layer.

22. In a thermoelectric heat pump assembly comprising semiconductor layers of n-type and p-type material having hot and cold junction surfaces, a first junction bridge element in the form of a metal member for freezing ice thereon in electrical contact with similar junction ends of said semiconductor layers, a rod firmly secured to said junction bridge, second junction bridge elements in electrical contact with the other junction surface of said semiconductor layers, and means attached to said rod for forcing the junction bridge elements towards the respective surfaces of said semiconductor layers.

23. In a thermocouple heat pump asembly comprising semiconductor layers of n-type and p-type material having hot and cold junction surfaces, a first junction bridge element in electrical contact with similar junction ends of said semiconductor layers, a rod firmly secured to said junction bridge, a second junction bridge comprising a tubing section inside which said rod is disposed, said tubing section being electrically connected with the other junction surfaces of said semiconductor layers, and means attached to said rod for forcing the junction bridge elements towards the respective surfaces of said semiconductor layers and serving to hold said rod in a central position.

24. A thermoelectric heat pump assembly as in claim 23 wherein said finned tubing is made from aluminum and includes a copper end element secured to said finned tubing at the end facing the semiconductive layer.

25. In a thermoelectric heat pump assembly of the type including layers of semiconductor material of n-type and p-type each having first and second connective surfaces adapted to be electrically connected to first and second junction bridge elements respectively, a first junction bridge element adapted to be electrically connected to the corresponding surface of at least one of said semiconductor elements, a rod firmly secured to said first junction bridge element, a second bridge element adapted to be electrically connected to the other surface of said one semiconductor element, and compression means secured to said rod for forcing said first and second junction bridge elements toward said semiconductor layer wherein the electric and heat conductive path through said second bridge element and said semiconductor element includes a pressure contact.

26. A thermoelectric heat pump assembly as in claim 25 wherein the abutting surfaces of said pressure contact are plated with a suitable metal for obtaining a permanent pressure contact with low electric resistance.

References Cited UNITED STATES PATENTS 3,035,416 5/1962 Wagner 136- 204 3,088,289 5/ 1963- Alex 62- 3 3,111,813 11/1963 Blumentritt 62--3 3,213,630 10/1965 Mole 62-3 3,234,048 2/1966 Nelson 6 23 3,273,347 9/1966 Elfving 62 -3 WILLIAM J. WYE, Primary Examiner. 

1. AN INDIVIDUAL THERMOELECTRIC SUBCOUPLE COMPRISING A SINGLE SEMICONDUCTIVE LAYER OF N-TYPE OR P-TYPE MATERIAL, HEAT DISSIPATING AND HEAT ABSORBING JUNCTION BRIDGE ELEMENTS IN ELECTRIC AND HEAT CONDUCTIVE CONNECTIONS WITH THE HOT AND COLD JUNCTION SIDES OF SAID SEMICONDUCTIVE LAYER, METAL CONDUCTORS ELECTRICALLY CONNECTED TO OPPOSITE SIDES OF SAID SEMICONDUCTIVE LAYER ADAPTED TO ELECTRICALLY CONNECT TO LATERALLY ADJACENT INDIVIDUAL SUBCOUPLES TO FORM THERMOELECTRIC COUPLES HAVING LATERALLY ADJACENT SUBCOUPLES, AND COMPRESSING MEANS FOR INDEPENDENTLY COMPRESSING EACH OF SAID INDIVIDUAL SUBCOUPLES TOGETHER TO PROVIDE ELECTRICAL AND HEAT CONDUCTIVE PRESSURE CONTACT BETWEEN THE PARTS CONSTITUTING SAID SUBCOUPLES. 